Levobunolol Hydrochloride Ophthalmic Solution

This article is compiled based on the United States Pharmacopeia (USP) – 2025 Edition

Issued and maintained by the United States Pharmacopeial Convention (USP)

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1 DEFINITION

Levobunolol Hydrochloride Ophthalmic Solution contains NLT 90.0% and NMT 110.0% of the labeled amount of levobunolol hydrochloride (C₁₇H₂₅NO₃ · HCl).

IDENTIFICATION

A. The retention time of the major peak of the Sample solution corresponds to that of the Standard solution, as obtained in the Assay.

Add the following:

B. The UV spectrum of the major peak of the Sample solution corresponds to that of the Standard solution, as obtained in the Assay. (USP 1- Dec-2019)

2 ASSAY

Change to read:

2.1 Procedure

Solution A: 1.0 g/L of (USP 1-Dec-2019) sodium 1-heptanesulfonate in water

Mobile phase: Methanol, glacial acetic acid, and Solution A (550:5:450)

Standard solution: 0.05 mg/mL of USP Levobunolol Hydrochloride RS in Mobile phase

Sample solution: Nominally equivalent to 0.05 mg/mL of levobunolol hydrochloride in Mobile phase from Ophthalmic Solution

2.2 Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: UV 254 nm. For Identi

cation B, use a diode array detector in the range of 200–400 nm. (USP 1-Dec-2019)

Column: 3.9-mm × 30-cm; 10-μm packing L1

Flow rate: 1.5 mL/min (USP 1-Dec-2019)

Injection volume: 20 μL

2.3 System suitability

Sample: Standard solution

2.4 Suitability requirements

Tailing factor: NMT 1.2

Relative standard deviation: NMT 1.5%

2.5 Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of levobunolol hydrochloride (C₁₇H₂₅NO₃ · HCl) in the portion of Ophthalmic Solution taken:

Result = (r_U /r_S ) × (C_S /C_U ) × 100

r_U = peak response from the Sample solution

r_S = peak response from the Standard solution

C_S = concentration of USP Levobunolol Hydrochloride RS in the Standard solution (mg/mL)

C_U = nominal concentration of levobunolol hydrochloride in the Sample solution (mg/mL)

Acceptance criteria: 90.0%–110.0%

3 IMPURITIES

3.1 Organic Impurities

Mobile phase: Prepare as directed in the Assay.

Standard solution: 0.01 mg/mL each of USP Levobunolol Hydrochloride RS and USP Edetate Disodium RS in Mobile phase

Sample solution: Nominally equivalent to 1 mg/mL of levobunolol hydrochloride in Mobile phase from Ophthalmic Solution

Chromatographic system and System suitability: Proceed as directed in the Assay using wavelengths of UV 254 and 400 nm.

[Note—The relative retention times for levobunolol and edetate disodium are 1.0 and 0.46, respectively.]

3.2 Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of any individual impurity at 254 nm in the portion of Ophthalmic Solution taken:

Result = (r_U/r_S)x(C_S/C_U ) × 100

r_U = peak response of each impurity from the Sample solution

r_S = peak response of levobunolol from the Standard solution

C_S = concentration of USP Levobunolol Hydrochloride RS in the Standard solution (μg/mL)

C_U = nominal concentration of levobunolol hydrochloride in the Sample solution (μg/mL)

Calculate the percentage of any individual impurity (at 400 nm) at the retention time of levobunolol (at 254 nm) in the portion of

Ophthalmic Solution taken:

Result = (r_U/r_S)x(C_S/C_U) × (1/F) × 100

r_U = peak response of the impurity from the Sample solution at 400 nm

r_S = peak response of levobunolol from the Standard solution at 254 nm

C_S = concentration of USP Levobunolol Hydrochloride RS in the Standard solution (μg/mL)

C_U = nominal concentration of levobunolol hydrochloride in the Sample solution (μg/mL)

F = relative response factor for the impurity, 0.2

Acceptance criteria

Individual impurity: NMT 1%

Total impurities: NMT 2.5%. Disregard any peak at 254 nm with the retention time of edetate disodium.

4 SPECIFIC TESTS

Antimicrobial Effectiveness Testing 〈51〉: Meets the requirements

Sterility Tests 〈71〉, Test for Sterility of the Product to Be Examined, Membrane Filtration: Meets the requirements

pH 〈791〉: 5.5–7.5

5 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in tight containers. Protect from light. Store at controlled room temperature.

USP Reference Standards 〈11〉

USP Edetate Disodium RS

USP Levobunolol Hydrochloride RS